The primary goal of this project is to understand how the early ability to modulate motor behavior forms the basis for the development of motor regulation over the early years of life, and how this process is modified by acute CNS injury and chronic stress on the developing nervous system. It extends our ongoing work by examining arousal effects on motor regulation while addressing practical issues associated with assessment and understanding of early precursors to developmental disabilities. Specific aims are (1) to study spontaneous and elicited motor activity during the neonatal period, including how this is modulated by arousal and related to attention modulation during this period, (2) to study specific hypothesis-driven marker tasks involving various sensory and environmental inputs on motor regulation from the neonatal period through the pre-school years (from newborn to 5 years), (3) to relate the ability to modulate motor activity in the early months of life to later autoregulatory components of motor behavior, (4) to evaluate the effect of chronic stress and acute CNS injury on this developmental process of motor regulation, and (5) to integrate findings on motor regulation with the types of dysfunction in motor skill that are prevalent in our high-risk population. While most studies of CNS injury and motor development in high-risk infants and children concentrate on factors such as incidence and degree of gross motor disabilities, this Subproject will look beyond direct and obvious damage to motor pathways by examining the effects of CNS injury from acute and chronic insult on the infant's ability to modulate motor activity. Studies will examine infants' modulation of early spontaneous and elicited movements, older infants' modulation of motor behavior under various sensory, cognitive, environmental, and social demands. The design is a longitudinal prospective study with 2 cohorts: 330 newly-recruited infants from the NICU tested from birth to 34 months and 275 previously-recruited children tested from 34 - 60 months. The longitudinal character of the study and its integration of motor regulation results from neonates through pre-schoolers with information on early injury, early attention-modulation capacity, and executive-function and linguistic development promise not only to advance theoretical knowledge of motor development and regulation but to suggest potential strategies for therapeutic intervention. This Subproject will use information on autoregulation from Core procedures as well as on gestures and social communication from Subproject II as they contribute to motor regulation.